The association between idiopathic inflammatory myopathy (IIM) and cancer has been extensively studied in adults. Many epidemiological studies demonstrated this association, which appears stronger for dermatomyositis (DM) than for polymyositis (PM). The first case suggesting an association between cancer and DM was reported in 1916. At present the reported incidence of cancer association with DM varies widely, from less than 7% to over 30%. Many early evidences came from case reports, but this association was later confirmed in case-control as well as in population-based studies. Ovarian cancer or breast cancer in females and lung cancer in males are the main malignancies associated with DM. Given the frequency of the association of dermatomyositis with cancer, for cost-effectiveness reasons it might be important to develop simple and appropriate diagnostic tests for identification of patients with DM, who may be at higher risk of developing a malignancy. Clinicians should plan follow-up schedules to optimize both cancer detection and treatment, and thus to improve patient survival. Many different clinical and serological signs have been suggested as possible predictive factors for malignancy in dermatomyositis: age, increased erythrocyte sedimentation rate (ESR), presence of cutaneous leukocytoclastic vasculitis, cutaneous rash and skin lesions as cutaneous necrosis and periungueal erythemas, neoplastic markers or dysphagia. The results of the different studies are quite discordant. Therefore, we conducted a systematic review of the scientific literature to evaluate the level of the risk of cancer in patients with dermatomyositis and to explore whether certain patient characteristics may be linked to different levels of cancer risk.